Head and body lengths of O. degus range from 125-195
mm and tail lengths are 105-165 mm. Weights are 170-300 g. Upperparts
are gray to brown, often with a tinge of orange. and the underparts
are creamy yellow. The tip of the tail is black. The first four
digits on all four feet are well developed, while the fifth
is considerably smaller. There are long bristles that extend
over the claws on the hind feet. Females have eight mammae.

O. degus is found on the west slope of the Andes at elevations
of up to 1,200 meters in fairly open areas near thickets, rocks,
or stone walls. Degus are diurnal, with the greatest amount
of activity occurring in the morning and late afternoon. Colonies
build extensive burrow systems with a main area usually located
beneath a shrubs or rocks, and complex tunnels and surface paths
radiating from it.

The
diet consists of grasses, leaves, bark, seeds and fruit, and,
during the dry season, is supplemented with the droppings of
cattle and horses. O. degus stores food for the winter.

The
Degu is the most common mammal of central Chile. It
has a strong social organization which is determined by group
territoriality. The primary defended territory is the central
burrow, where females of the same social group may rear their
young together.

It
is unclear if there is a specific breeding season for O.
degus, and there is speculation that the presence of a male
may be necessary for the female to begin ovulation. Gestation
lasts about 90 days with litter sizes ranging from 1-10 offspring.
In captivity, babies have been born both fully furred with eyes
open, and sparsely furred with eyes opening at about 2-3 days
of age. Birthweight is about 14 grams. The baby Degus must nurse
for at least 14 days and usually for about 4 weeks. Parents
cut grass and bring it into the burrows for their young. The
average age at which sexual maturity is reached is about 6 months.

O. degus is found in Chile, west slope of the Andes between
Vallenar and Curico, to 1,200 m.